This invention relates to an apparatus for the gas-phase processing of disk-shaped workpieces. In particular, it serves to lengthen the service life of reactor components during the processing of semiconductor substrates in closed reaction spaces with relative media.
In constructing reactors for the gas-phase processing of disk-shaped substrates, particularly reactors for the chemical deposition from the vapor phase (CVD) or for plasma chemical etching, it is an important objective that conditions for achieving processing effects (such as temperature, distribution of the reaction gas, guidance of the waste gas, plasma density distribution) are produced as far as possible only at the substrate surface that is to be processed and that otherwise the inner walls of the reactor space are spared the processing effects (layer deposition, etching) or the accompanying phenomena of the processing effect (deposition of reaction by-products).
This objective cannot be achieved with conventional reactor constructions. Known solutions, such as heating the substrate by radiant heat, short paths for guiding the gas in the reactor and a local generation of the plasma are necessary partial steps for the solution of this problem. Finite gradients of the distribution functions of the reaction conditions in the reactor always lead to parasitic processing effects outside of the substrate zone.
Deposition of by-products of the reaction is frequently linked to those very conditions, which deviate from those for achieving the desired processing effect. Such conditions generally are present at the reactor walls.
It is an object of the invention to process disk-shaped substrates in high quality and to decrease the work involved in cleaning the reactor required for the gas-phase processing.